The snap-to-trail feature utilizes OpenStreetMap data. Use OSM-based sources like Gaia Topo, OpenHikingMap HD, OpenLandscapeMap HD, and OpenCycleMap HD for best results. You can tap the layers icon to change the map source during route creation:

Tap and drag the blue dot to the start of the trail

Tap and hold anywhere on the screen to plot your next point

While using a snap-to-trail mode, your route will snap to existing trail data

An elevation profile will appear at the bottom of the screen. Tap and slide your finger across the profile to see the corresponding location along your route.

When you finish plotting the route, tap Save at the top-right of the screen.

Finally, name your route and select maps for download, then tap Save again.

Saving the route immediately initiates the download of your selected layers. Leave the app in the foreground and connected to the internet to complete the downloads.

Note: You can skip map downloads by toggling off all of the layers before saving.